1. Technical Field
The present invention relates generally to a scheduling apparatus and method, and more particularly to a scheduling apparatus and method that can minimize negotiations between nodes within a network.
The present invention has been derived from research conducted for Project for Research into Resilient/Fault-Tolerant Autonomous Networking Technology based on the Physical Attributes, Relationships and Roles of IoT Devices sponsored by the Korean Ministry of Science, ITC and Future Planning and the Institute for Information & Communications Technology Promotion [Project Management Number: No. B0190-16-2017] and Project for the Promotion of University ICT Research Centers sponsored by the Korean Ministry of Science, ITC and Future Planning and the Institute for Information & Communications Technology Promotion [Project Management Number: IITP-2017-R0992-17-1023] in 2016, and National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (No. 2016R1A5A1012966).
2. Description of the Related Art
Recently, interest in a ubiquitous computing environment in which all things are equipped with computing, sensing, and communication functions has increased. A ubiquitous computing environment has attracted attention as the core technology of sensor network technology that performs the functions of detecting and controlling environments outside humans.
A wireless sensor network based on such a ubiquitous computing environment, e.g., ZigBee, is wireless communication technology developed for wireless application services for civil and industrial fields requiring low power, low cost and small amounts of data. ZigBee defines network, security and application layers, i.e., higher-level layers, based on the IEEE 802.15.4 standard that defines a physical layer and a medium access control (MAC) layer, i.e., layers lower than the network layer.
Recently, such a wireless sensor network has been applied to Internet of Things (IoT) communication, and has been used for communication between a plurality of nodes. Nodes for the construction of a wireless sensor network may implement a network by using a centralized method or a distributed method.
For example, when a network is implemented using the centralized method, a single representative node controls the scheduling operations of all nodes present in the same network. When a single node controls overall communication within a network as described above, the corresponding node requires large amounts of information. Accordingly, in the network constructed using the centralized method, when there is a rapid change in a network topology, the transfer of large amounts of data from all nodes to a representative node is required for scheduling, and thus it is impossible to deal with this situation. Furthermore, disadvantages also arise in that all the nodes require additional energy and bandwidth resources attributable to the transfer of the data to the representative node and a long period of time is required for the initialization of the network.
Furthermore, when a network is implemented using the distributed method, all nodes themselves perform scheduling operations. In this case, each of the nodes must communicate with adjacent nodes in order to avoid a collision that occurs when interfering nodes use the same channel at the same time. This network requires a specific negotiation protocol. In the case where a network is constructed using the centralized method, all information is collected at a central node and scheduling is determined, whereas in the case where a network is constructed using the distributed method, all the nodes within the network collect small amounts of information from adjacent nodes and perform scheduling via a separate negotiation protocol. As a result, the network implemented using the distributed method is more robust to a rapid change in a network topology than the network implemented using the centralized method. However, each of the nodes must submit to additional traffic during the process of negotiation with adjacent nodes, and thus consumes additional energy and network resources. Furthermore, from the point of view of the overall network, the network implemented using the distributed method has the disadvantage of lacking visibility because scheduling cannot be performed based on the overall network.
In order to overcome these disadvantages, there has been a need for a network which can minimize negotiations between nodes on a wireless sensor network and which can also minimize collisions attributable to data transmission between nodes.
Accordingly, there is a need for a technology for overcoming the above-described problems.
Meanwhile, the above-described background technology corresponds to technical information that has been possessed by the present inventor in order to contrive the present invention or that has been acquired in the process of contriving the present invention, and cannot be necessarily viewed as a well-known technology that had been known to the public before the filing of the present invention.